This is an improvement of U.S. Pat. No. 4,944,550. This patent discloses a complicated actuation system that is designed to move the enclosure or cover over the bed of the pick-up truck. This is a permanent installation and may interfere with the loading operation of the vehicle. The present invention is designed to hydraulicaly operate the cover which at the same time can be removed. A hand operated truck cover is found in U.S. Pat. Nos. 4,693,508 and 3,773,380 which can be slidingly operated by hand. It has been found that certain persons cannot manipulate the somewhat heavy cover such as elderly persons or persons having some disability. The aim of this invention is to simplify the operation of moving the cover hydraulically.